快速命中：
- 了解时间敏感的网络如何为工业以太网带来决定论。
- Understanding why Time-Sensitive Networking only addresses data transfer in the OSI model.
- 工业以太网协议如何解决应用程序使用，OSI模型的较高级别。
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Read the transcript below: |
Welcome toTake Fivewith自动化世界. I’m David Greenfield, Director of Content, and today we’re going to look at why industrial Ethernet protocols are still needed with Time-Sensitive Networking.
但首先,以确保每个人都在同一page, let’s start by explaining Time-Sensitive Networking or TSN. Essentially, TSN is a way of providing determinism on Ethernet. And the lack of determinism in standard Ethernet was always one of the biggest drawbacks to Ethernet’s use as a plant floor network. But since determinism is largely only required for high-speed or high-precision control applications, Ethernet has slowly but surely been gaining ground across manufacturing and processing facilities over the past two decades in all other areas of operation. In areas where determinism is needed, deterministic fieldbus technologies have largely remained in place.
以太网缺乏决定论的原因是它处理由其携带的信息包。当多个设备在任何业务网络上是典型的网络上进行通信时，以太网避免了数据碰撞，这是在同时发送多个数据包时发生的，而这些数据碰撞是通过持有一些信息的数据包，而其他信息则通过。这样可以避免在碰撞期间删除数据包时的潜在信息丢失。
Of course, this is a very simplistic explanation of how Ethernet handles data transmission without getting into the roles of routers, switches, and MAC and IP addresses. But hopefully it gets across the idea that some packets of data can be held up while others pass through. For most information packets, this isn’t a problem. For example, if it takes a fraction of a second longer for you to get your email, not only will it not impact your operations—you won’t even notice it. But this kind of delay can cause problems with high-speed and high-precision machinery.
That’s where TSN comes in. TSN is an IEEE 802.1 standard originally developed for the audio/visual industry to better synchronize audio and video. But the deterministic communication it provides can be used for Ethernet-based control traffic, because it ensures that critical control communications not only get through unimpeded by other traffic on the network, but that control communications are treated with the highest priority.
The first step in understanding how industrial Ethernet protocols function with TSN is to understand that TSN only addresses network functions at Layer 2—the Data Link layer—of the Open System Interconnection model, often referred to as the OSI model. Tom Burke, the global strategic advisor at theCC-Link Partner Association，支持CC-LINK IE工业以太网协议，他说，由于TSN仅在此第2层级别运行，因此仅负责以确定性的方式将数据从一个地方获取，而无需查看数据是什么。这意味着，通过TSN传输的数据需要完成的任何操作都以满足应用程序要求的高级层进行处理。这是工业以太网协议发挥作用的地方。伯克说，这些协议和TSN围绕融合共同起作用 - 大多数工业以太网协议不允许在同一网络上合并不同种类的流量。因此，TSN实质上创建了一个系统，该系统通过允许多种流量类型在以确定性方式处理时共享同一网络来提供必要的灵活性。
现在，伯克（Burke）建议，对于机器建造者和最终用户，以充分利用与TSN兼容的以太网协议的优势，他们应该仔细研究其规格，以确保它可以解决其预期应用程序的要求。他强调，合适的协议应涵盖I/O，运动控制和安全性。
And Burke notes that CC-Link IE TSN is an industrial Ethernet protocol that combines Gigabit bandwidth and TSN functionalities. The CC-Link IE TSN protocol uses layers 3 to 7 of the OSI model to build on the layer 2 TSN capabilities. Burkes says that, by doing this, it allows I/O, motion, and safety control to be integrated with standard TCP/IP traffic over Ethernet in a deterministic way.
除了CC-Link IE TSN外Profinet，，，，以太猫，，，，EtherNet/IP， 乃至SERCOS—which has long been recognized specifically for its deterministic capabilities.
So I hope you found this服用5episode helpful.
